clojure.core/str

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Type: function Added: Clojure 1.0 Examples: 8 Runnable: 7

([] [x] [x & ys])

With no args, returns the empty string. With one arg x, returns x.toString(). (str nil) returns the empty string. With more than one arg, returns the concatenation of the str values of the args.

Examples

by Dimagog on 2010-07-15 ▶

"some string" "some string" (str) "" (str nil) "" (str 1) "1" (str 1 2 3) "123" (str 1 'symbol :keyword) "1symbol:keyword" ;; A very common usage of str is to apply it to an existing collection: (apply str [1 2 3]) "123" ;; compare it with: (str [1 2 3]) "[1 2 3]"

by belun on 2010-09-28 . May have evaluation errors. ▶

;; Destructuring with a string, getting just a few characters from it (let [[first-char second-char] "abcde"] (prn 'first= first-char) (prn 'second= second-char)) first= \a second= \b nil ;; More destructuring with a string (let [[first-char second-char & rest-of-chars] "abcde"] (prn 'first= first-char) (prn 'second= second-char) (prn 'rest= rest-of-chars)) first= \a second= \b rest= (\c \d \e) nil ;; Destructuring, getting the first character of a string ;; and then a reference to the entire string (let [[first-char :as all-the-string] "abcde"] (prn 'first= first-char) (prn 'all= all-the-string)) first= \a all= "abcde" nil

by Lacty on 2016-08-12 ▶

(str "L" "a") "La" (str "L" 5 "a") "L5a"

by phreed on 2018-02-07 ▶

;; sometimes when printing lazy sequences you do not get what you want. (str (take 5 (range 10))) ;=> "clojure.lang.LazySeq@1b554e1" ;; in those cases `pr-str` to the rescue. (pr-str (take 5 (range 10))) ;=> "(0 1 2 3 4)"

by operasfantom on 2018-05-22 ▶

;; be careful with java.lang.Double to java.lang.String conversion (str -128004972.0) ;=> "-1.28004972E8"

by RayceeM on 2019-01-14 ▶

;; Using str in maps (def user-map {:fname "Jane" :sname "Doe"}) ;;getting the value of the first key (:fname user-map) ;=> "Jane" (str (:fname user-map) " " (:sname user-map)) ;=> "Jane Doe"

by themustafabasit on 2020-09-09 ▶

(str nil) ;; => "" (str true) ;; => "true" (str false) ;; => "false"

by E-A-Griffin on 2025-08-20 ▶

;; Characters are converted to strings of size 1 (str \space) ;; => " " ;; Occasionally you may want a string representation of clojure's character syntax ;; for a particular character, wrapping the char in a data structure ;; before calling [[str]] is one workaround (defn char->str [c] (let [s (str [c])] (subs s 1 (dec (count s))))) ;; => #'user/char->str (char->str \space) ;; => "\\space"

See also

• clojure.core/pr (2)
• clojure.core/prn
• clojure.core/pr-str (3)
• clojure.core/prn-str (2)
• clojure.core/print-str
• clojure.core/println-str

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